1 /* $KAME: if_nameindex.c,v 1.8 2000/11/24 08:20:01 itojun Exp $ */
2
3 /*-
4 * Copyright (c) 1997, 2000
5 * Berkeley Software Design, Inc. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 *
13 * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 *
25 * BSDI Id: if_nameindex.c,v 2.3 2000/04/17 22:38:05 dab Exp
26 */
27
28 #include <sys/cdefs.h>
29 #ifndef FSTACK
30 __FBSDID("$FreeBSD$");
31 #endif
32
33 #include <sys/types.h>
34 #include <sys/socket.h>
35 #include <net/if_dl.h>
36 #include <net/if.h>
37 #include <ifaddrs.h>
38 #include <stdlib.h>
39 #include <string.h>
40
41 /*
42 * From RFC 2553:
43 *
44 * 4.3 Return All Interface Names and Indexes
45 *
46 * The if_nameindex structure holds the information about a single
47 * interface and is defined as a result of including the <net/if.h>
48 * header.
49 *
50 * struct if_nameindex {
51 * unsigned int if_index;
52 * char *if_name;
53 * };
54 *
55 * The final function returns an array of if_nameindex structures, one
56 * structure per interface.
57 *
58 * struct if_nameindex *if_nameindex(void);
59 *
60 * The end of the array of structures is indicated by a structure with
61 * an if_index of 0 and an if_name of NULL. The function returns a NULL
62 * pointer upon an error, and would set errno to the appropriate value.
63 *
64 * The memory used for this array of structures along with the interface
65 * names pointed to by the if_name members is obtained dynamically.
66 * This memory is freed by the next function.
67 *
68 * 4.4. Free Memory
69 *
70 * The following function frees the dynamic memory that was allocated by
71 * if_nameindex().
72 *
73 * #include <net/if.h>
74 *
75 * void if_freenameindex(struct if_nameindex *ptr);
76 *
77 * The argument to this function must be a pointer that was returned by
78 * if_nameindex().
79 */
80
81 struct if_nameindex *
if_nameindex(void)82 if_nameindex(void)
83 {
84 struct ifaddrs *ifaddrs, *ifa;
85 unsigned int ni;
86 int nbytes;
87 struct if_nameindex *ifni, *ifni2;
88 char *cp;
89
90 if (getifaddrs(&ifaddrs) < 0)
91 return(NULL);
92
93 /*
94 * First, find out how many interfaces there are, and how
95 * much space we need for the string names.
96 */
97 ni = 0;
98 nbytes = 0;
99 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
100 if (ifa->ifa_addr &&
101 ifa->ifa_addr->sa_family == AF_LINK) {
102 nbytes += strlen(ifa->ifa_name) + 1;
103 ni++;
104 }
105 }
106
107 /*
108 * Next, allocate a chunk of memory, use the first part
109 * for the array of structures, and the last part for
110 * the strings.
111 */
112 cp = malloc((ni + 1) * sizeof(struct if_nameindex) + nbytes);
113 ifni = (struct if_nameindex *)cp;
114 if (ifni == NULL)
115 goto out;
116 cp += (ni + 1) * sizeof(struct if_nameindex);
117
118 /*
119 * Now just loop through the list of interfaces again,
120 * filling in the if_nameindex array and making copies
121 * of all the strings.
122 */
123 ifni2 = ifni;
124 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
125 if (ifa->ifa_addr &&
126 ifa->ifa_addr->sa_family == AF_LINK) {
127 ifni2->if_index =
128 LLINDEX((struct sockaddr_dl*)ifa->ifa_addr);
129 ifni2->if_name = cp;
130 strcpy(cp, ifa->ifa_name);
131 ifni2++;
132 cp += strlen(cp) + 1;
133 }
134 }
135 /*
136 * Finally, don't forget to terminate the array.
137 */
138 ifni2->if_index = 0;
139 ifni2->if_name = NULL;
140 out:
141 freeifaddrs(ifaddrs);
142 return(ifni);
143 }
144
145 void
if_freenameindex(struct if_nameindex * ptr)146 if_freenameindex(struct if_nameindex *ptr)
147 {
148 free(ptr);
149 }
150